Bài làm
31 x ( -72 ) - 31 x 70 + 31 x 2
= 31 x ( -72 + 70 + 2 )
= 31 x 0
= 0
31 . ( - 72 ) - 31. 70 + 31 . 2
= 31[ ( - 72 ) + 70 + 2 ]
= 31 [ (-72) + 72 ]
= 31 . 0 = 0
31 x ( - 72 ) - 31 x 70 + 31 x 2
= 31 x [ ( - 72 ) + ( 70 + 2 ) ]
= 31 x [ ( - 72 ) + 72 ]
= 31 x 0
= 0
VERY GOOD!!!
31.(-72)-31.70+31.2
=31.[(-72)-70+2]
=31.[(-72)-72]
=31.0
=0